Add a symbol property to get current option chain's option

[legendecas]

Now it's not possible to access option chains' current opts outside the chain callback, what if we can access the current opts of the option chain with a predefined symbol?

optionChain.optsSymbol = Symbol('option-chain-opts')

const fn = optionChain(optionDefinition, printOptionsAndArgs);
fn.foo[optionChain.optsSymbol] //=> {foo: true};